In an exposure apparatus that uses EUV light, since the wavelength of the EUV light is as short as 13.5 nm and is attenuated in the atmosphere, an exposure optical system is provided in a vacuum. Since a reticle stage is placed in the vacuum, a vacuum chuck cannot be used for an EUV mask namely, and instead, an electrostatic chuck system is adopted.
However, when the reticle is adsorbed to an electrostatic chuck, if foreign matters are present between the reticle and the electrostatic chuck, the reticle is deformed and a pattern transferred onto a wafer is distorted.